Perforating apparatus



Oct. 8, 1963 s, T, DUEKER PERFORTING APPARATUS Filed Aug. 28, 1958 Byammla/ SZOW/ey 7: ue//er' INVENTOR.

V llllll l AATTORNEY United States Patent() 3,106,130 PERFORMING APPARATUS Stanley T. Dueker, Houston, Tex., assignor to Schlumberger Well Surveying Corporation, Houston, Tex., a

corporation of Texas Filed Aug. 2S, 1958, Ser. No. 757,838 7 Claims. (Cl. S9-1) This invention relates to perforating apparatus and more particularly pertains to a new and improved closure sealing arrangement for a gun bore.

Among the objects of the present invention is the provision of a novel closure sealing arrangement for a gun bore wherein a direct seal may lbe achieved without the use of a sealing agent or member.

Another object of the present invention is to provide a new and improved end closure sealing arrangement for a gun bore which permits the gun -bore to have a longer effective length than heretofore possible.

Still another object of the present invention is to provide a new and improved closure arrangement for a gun bore wherein the sealing surfaces for the closure are shielded from the erosive and deformative effects of the powder blast or hot gases.

Yet another object of the present invention is to provide a new and improved closure sealing arrangement for a gun bore wherein the primary sealing surface between the closure and gun barrel is not subjected to sliding action when the closure is expelled.

A further object of the present invention is to provide a new and improved closure sealing arrangement for a gun bore wherein the sealing pressure between the sealing surfaces increases with increased external pressure on the closure.

These and other objects are obtained by a perforating apparatus having a gun -barrel with a bore surrounded by an annular groove of appropriate shape. The distance between the walls of the groove near the forward surface of the barrel is sufficient to receive the annular rim of a generally dome-shaped closure. The groove -is tapered inwardly of the forward barrel surface so that the rim of the closure is deformed when pressure is applied to the closure dome, hence increasing the sealing pressure and thereby directly sealing the closure to the gun barrel without the need of sealing agents.

The novel features of the present invention are set forth with particu-larity in the appended claims. The present invention both as to organization and manner of operation together with further objects and advantages thereof may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings 4in which:

FIG. 1 is a transverse sectional View through a gun unit featuring a closure arrangement embodying the present invention shown disposed within a well bore; l

iFIG. 2 is an enlarged view in cross section of the closure illustrated in FIG. 1 and shown prior to insertion in a gun barrel;

FIG. 3 is an enlarged view in cross section of a portion of the forward end of a gun barrel of the gun unit of FIG. 1 shown prior to insertion of the closure;

FIG. 4 illustrates an initial step in the assembly of the elements shown in FIGS. 2 and 3; and

FIG. 5 illustrates the nal assembly of the elements shown in FIGS. 2 and 3. p l

Referring now to FIG. 1, there is shown a casing 8 cemented in the customary manner within-a borehole 9 traversing earth formation 1li. The casing may contain the usual conditioning liquid 11 and to perforate the casing an elongated perforating gun 12 is lowered on a wire line (not shown) in the usual fashion. The perforating apparatus is of general cylindrical configuration .in horizontal cross section and has a lateral gun barrel 13 threadedly received in a chamber 14. The rearward end of chamber 14 and the rearward end of gun barrel V13 form a powder chamber which contains an explosive material 15. A gun bore 16 extends between forward and rearward end faces 17, 18 of the gun barrel and a bullet 19 having a rearward end portion disposed within the explosive material 15 is received in the bore. A conventional detonator 20 connected to an electrical ignition circuit (not shown) serves to detonate the explosive material 15. The forward end 21 of the gun barrel as well as the detonator 20 are provi-ded with suitable seals 22, 22 to fluidly seal off the interior of chamber 14 from the well uid 11. In accordance with the present invention, a closure 23 is received within an annular recess 24 in the gun barrel to lluidly seal the gun bore 16.

While only a single gun barrel arrangement is illustrated in FIG. 1 in the interest of simplicity, actually the perforating apparatus is provided with a plurality of gun barrels superimposed along a vertical axis, each of which is -similarly constructed. The construction of the perforatinggun itself does not comprise any part of the present invention which is directed to the closure 23 and annular sealing groove 24 within the gun barrel as will hereinafter become more apparent.

As shown in FIG. 2, the closure member 23 initially comprises a thin-walled dome-shaped or generally spherical imperforate head portion 25 and an integral cylindrical -deformable rim 26 including inner and outer substantially concentric wall surfaces 27, 23 and an end surface 29. The member 23 as contemplated in the invention may be constructed of a suitable malleable material of proper strength to withstand the pressures encountered, for example, brass. Of course, other appropriatc materials may be employed, such as copper, aluminum or a suitable plastic as Bakelite.

As best seen in FIG. 3, the annular recess 24 at the forward end 21 of gun barrel 13 is concentrically arranged with respect to the gun bore 16. Recess 24Vis comprised of a cylindrical surface portion 31 having a larger diameter than bore 16 and extends coaxially with respect to the axis of bore 16 to a perpendicular bottom surface 32. A frusto-conical surface portion 33 of a mean diameter smaller than the diameter of surface 31 extends between -bottom surface 32 and a perpendicular surface 17 that lies in a plane between the planes defined -by the outer surface 34 and the bottom surface 32 and that terminates at bore 16. Surface 33 is inclined away from surface 32 in a direction towards the axis of bore 16 and the dimensions of the various surfaces will be apparent from the discussion to follow.

To install closure 23 within the `recess 24, it is positioned as shown in FIG. 4 from which it can be seen that the outer wall 28 of rim 26 tightly ts within the cylindrical surface 31. The rim 26 has a thickness, i.e., the distance between surfaces 27, 28, which is smaller than the spacing between cylindrical surface 31 and the annular edge 35 of surface 17. The thicknessl of the rim 26 is, however, greater than the spacing between surface 34 and the inner annular edge 36 of bottom surface 32 so that inner wall 27 engages the inclined sealing surface 33 at a point well above the bottom surface 32 of recess 24.

The elements shown in FIG. 4 are then placed in a conventional press and a load or force is applied by a spherically shaped ram member to cause the closure 23 to move in a direction toward surface 32. As a result, the inner wall 27 of closure 23 deforms to provide a surface 27 which mates with the inclined surface 33 of recess 24. The inner and outer walls 27, 28" of closure 23 are thus forced against walls 31, 33 of recess 24 by the wedging effect of inclined wall 33 thereby providing a metal-tometal seal. Increased pressure, of course, causes an increased sealing force on the .walls 27, 28 of the closure.

It will be apparent from the foregoing description that the recess 24 and closure 25 are arranged so as to permit a metal-to-metal seal in which the sealing pressure increases as the force applied to the closure is increased. Thus, when the perforating gun is lowered into a liquid containing well, as shown in FIG. 1, the increase in hydrostatic pressure with depth produces a better seal and well liquid cannot enter bore 16. At the appropriate depth, igniter 20 is energized thereby to detonate explosive 15 and bullet 19 is propelled through the bore. Because of the configuration of recess 24, the gun bore 15 is not appreciably shortened to accommodate the closure 23 and the penetrating quality of the bullet is not impaired. Moreover, the sealing surfaces 31, 33 of the recess 24 are shielded from the direct effects of powder blast and hot gases which might otherwise verode or deform these surfaces. Further, since the recess has a narrow bottom surface 32 and a larger throat space between wall 31 and edge 35 and the mass of closure 24 can be relatively small, 'the closure 24 is expelled with a minimum of force and without sliding action on inclined surface 33. Hence, movement of the bullet out of the bore 16 is not impaired.

Of course, numerous variations can be made in the typical embodiment described above without departing from the scope of the invention. For example, the surface 31 could be inclined with respect to the axis of bore 16 instead of or in addition to the inclination of wall 33. The invention, therefore, is not to be restricted to the specific form shown by way of illustration, but comprehends all such modifications as come within the scope of the following claims.

What is claimed is:

1. In a gun perforator adapted to be placed in a borehole containing well fluid, the combination of: a gun barrel having a bore with a central axis, said bore extending be tween forward and rearward end surfaces of the gun barrel and being sized so as to receive a projectile therein, said barrel having an annular groove about said bore and in said forward surface including inner and outer wall portions and a bottom wall portion, said inner and outer wall portions being arranged transversely to said forward surface, at least one of said wall portions being disposed at an angle relative to said central axis so that the width of the groove adjacent the forward surface is greater than the width of the groove inwardly of the said forward surface; a closure member for said bore having an imperforate portion and an integral, cylindrical, deformable rim sized to be received within said groove adjacent to the forward surface but of a thickness greater than the width of said groove at the section thereof inwardly of said forward end surface and short of said bottom wall portion so that said rim is deformable by the progressively narrower width of the groove when pressure is applied to the said closure member whereby a seal is provided between said closure and said gun bore.

2. In a gun perforator adapted to be placed in a borehole containing well fluid, the combination of: a gun barrel having a bore with a central axis, said bore extending between forward and rearward surfaces of the gun barrel and being sized so as to receive a projectile therein, said barrel having an annular groove about said bore and in said forward surface including inner and outer wall portions disposed transveresly to said forward surface and a bottom wall portion adjoining the lower ends of said inner and outer wall portions, one of said inner and outer wall portions being inclined relative to said central axis so that the width of the groove adjacent the forward surface is greater than the width of the groove inwardly of the said forward surface; a closure member for said bore having an imperforate head portion and an integral, cylindrical, deformable rim sized to be received within said groove adjacent to the forward surface but of a thickness greater than the width of said groove at the section thereof inwardly of said forward end surface and short of said bottom wall portion so that said rim is deformable by the progressively narrower width of the groove when pressure is applied to the said closure member whereby a seal is provided between said closure and said gun bore.

3. In a gun perforator adapted to be placed in a borehole containing well fluid, the combination of: a gun barrel having a bore with a central axis, Vsaid bore extending between forward and rearward surfaces of the gun barrel and being sized so as to receive a projectile therein, said barrel having an annular groove about said bore and in said forward surface including inner and outer wall portions disposed transversely to said forward surface and a bottom wall portion adjoining the lower ends of said inner and outer wall portions, said inner wall portion being inclined downwardly and outwardly relative to said central axis so that the width of the groove adjacent the forward surface is greater than the width of the groove inwardly of the said forward surface; a closure member for said bore having an imperforate head portion and an integral, cylindrical, deformable rim sized to be received within said groove adjacent to the forward surface but of a thickness greater than the width of said groovey at the section thereof inwardly of said forward end surface and short of said bottom wall portion so that said rim is deformable by the progressively narrower width of the groove when pressure is applied to the said closure member whereby a seal is provided between said closure and said gun bore.

4. In a gun perforator adapted to be placed in a borehole containing well iiuid, th-e combination of: a gun barrel having an outer surface, a bore disposed transversely tosaid outer surface with a central `axis and a grooved recess circumscribing said bore, said recess including a cylindrical surface having a larger diameter than said bore and extending coaxially with respect to said axis, a bott-om `surface arranged perpendicular to said central axis and adjoining said cylindrical surface, a frusto-conical surface of a mean diameter smaller than the diameter of said cylindrical surface adjoining and inclined away from said bottom surface towards said central axis and a forward surface between said conical surface and said bore lying in a plane perpendicular to said axis and spaced between the planes defined by said outer surface and said bottom sunface; a closure member for said bore having an imperforate head portion and an integral, cylindrical, deformable rim sized to be received between the said cylindrical `surfaces and frustoconical surface at a point adjacent the said forward surface but lof a thickness greater than the width of said bottom surface inwardly of said forward surface and short of said bottom surface of said groove so that said rim is deformable by the progressively narrower width of the groove when pressure is applied to said closure member whereby a seal is provided between said closure and said gun bore.

5. In a gun perforator adapted `to Ibe placed in a borehole containing well uid, the combination of: a body member having a bore with a central axis, said bore extending between forward and rearward end surfaces, said body member having an annular groove about said bore and in said forward surface including inner and louter wall portions and a bottom wall portion, said inner and Outer wall portion being arranged transversely to ysaid forward surface, at least one of said wall portions being disposed yat an angle relative to said central axis so that the width of the groove adjacent the forward surface is greater than the width of the gro-ove inwardly of said forward surface; a closure member for said bore having an imperforate portion and an integral, cylindrical, deformable rim sized to be received within said groove adjacent to the forward surface but of a thickness greater than the width of said groove inwardly of said forward end surface and short of said bottom wall portion so that said rim is deformable by the progressively narrower width of the groove when pressure is applied tto the said closure member whereby 1a seal is provided between said closure and said bore.

6. Well perforating apparatus for use in a fluid-containing well comprising: an integr-al reusable body member having a bore opening centrally of the forward Surface of `said body member, said body member having an annular groove relieved from said forward surface about the opening of said bore, the outer wall of said groove geing cylindrical, the inner wall of said groove having an inward taper forwardly of said body member and terminating at an annular shoulder in common with said bore short of said forwardsurface, and an integral imperforate closure member having a generally circular portion to close the opening of said bore and a deformable continuous annular rim thereabout directed rearwardly of said circular portion and sized `for conforming press-itted reception in `said groove in direct annular sealing relation with the respective walls of said groove short of the bottom of said groove, said circular portion being of a borehole containing well iluid, lthe combination of: an integral gun barrel having a forward end surface and a uniform diameter bore terminating at an annular lip insubstantially uniform thickness to be received Within the prole of said outer surface and forwardly spaced with respect to said shoulder, whereby said closure member may be displaced rearwardly by increasing Well fluid pressure to deform said rim into more tightly sealed relation in said groove.

7. In a gun perforator adapted to be placed in a wardly of said forward end surface for passage of a bullet therethrough, said barrel further lhaving :an annular groove between said lip and said forward end surface dened by annular Walls converging rearwardly of said lip, and a closure member for said bore having a circular portion to span said lip and a deformable rim portion sized for press-tted reception in said groove, said rim portion having interior and exterior walls which converge rearwardly in conformance with the Walls of said groove but short of the bottom of said groove when received therein whereby a seal is provided between said closure and said bore.

References Cited in the le of this patent UNITED STATES PATENTS 1,939,335 Buschman et al Dec. 12, 1933 2,210,125 Raymond et al Aug. 6, 1940 2,216,144 Tureohek Oct. 1, 1940 2,250,056 Alexander July 22, 1941 2,308,006 Henderickson Jan. 12, 1943 2,687,823 Whitmore Aug. 31,1954 2,708,408 Sweetman May 17, 1955 2,849,953 Delacour Sept. 2, 1958 

1. IN A GUN PERFORATOR ADAPTED TO BE PLACED IN A BOREHOLE CONTAINING WELL FLUID, THE COMBINATION OF; A GUN BARREL HAVING A BORE WITH A CENTRAL AXIS, SAID BORE EXTENDING BETWEEN FORWARD AND REARWARD END SURFACES OF THE GUN BARREL AND BEING SIZED SO AS TO RECEIVE A PROJECTILE THEREIN SAID BARREL HAVING AN ANNULAR GROOVE ABOUT SAID BORE AND IN SAID SURFACE INCLUDING INNER AND OUTER WALL PORTIONS AND A BOTTOM WALL PORTION, SAID INNER AND OUTER WALL PORTIONS BEING ARRANGED TRANSVERSELY TO SAID FORWARD SURFACE, AT LEAST ONE OF SAID WALL PORTIONS BEING DISPOSED AT AN ANGLE RELATIVE TO SAID CENTRAL AXIS SO THAT THE WIDTH OF THE GROOVE ADJACENT THE FORWARD SURFACE IS GREATER THAN THE WIDTH OF THE GROOVE INWARDLY OF THE SAID FORWARD SURFACE; A CLOSURE MEMBER FOR SAID BORE HAVING AN IMPERFORATE PORTION AND AN INTEGRAL, CYLINDRICAL DEFORMABLE RIM SIZED TO BE RECEIVED WITHIN SAID GROOVE ADJACENT TO THE FORWARD SURFACE BUT OF A THICKNESS GREATER THAN THE WIDTH OF SAID GROOVE AT THE SECTION THEREOF INWARDLY OF SAID FORWARD END SURFACE AND SHORT OF SAID BOTTOM WALL PORTION SO THAT SAID RIM IS DEFORMABLE BY THE PROGRESSIVELY NARROWER WIDTH OF THE GROOVE WHEN PRESSURE IS APPLIED TO THE SAID CLOSURE MEMBER WHEREBY A SEAL IS PROVIDED BETWEEN SAID CLOSURE AND SAID GUN BORE. 